What is the name respiratory pigment in humans?

The respiratory pigment in humans is haemoglobin. Haemoglobin is a protein found in red blood cells that transports oxygen from the lungs to the rest of the body. It also transports carbon dioxide from the body to the lungs to be exhaled. Haemoglobin is composed of four polypeptide chains, each of which is folded into a globin domain and contains a haem group. The haem group consists of an iron ion bound to a porphyrin ring. The oxygen molecule binds to the iron ion in the haem group.